This invention generally relates to a cemented carbide ball end mill for machining an aluminum alloy, and more particularly to an improvement in the configuration of and in a coating film for a cemented carbide ball end mill capable of performing dry machining.
Hitherto, when machining an aluminum alloy with a cemented carbide ball end mill, in order to prevent the melted aluminum alloy from being deposited on the machine tool, the aluminum alloy has usually been machined while applying water-soluble cutting fluid for promoting lubricating action. In recent years, however, because of a corrosive property of the water-soluble cutting fluid or a difficulty in handling of the cutting fluid as industrial waste, demand for machining an aluminum alloy by a cemented carbide ball end mill without using the cutting fluid, or needs for so-called dry machining have been rising.
A problem posed when machining an aluminum alloy with a cemented carbide ball end mill is the deposition of the melted aluminum alloy to cutting edges of the machine tool. Conventional cemented carbide ball end mill tools suffer a considerable deposition of melted aluminum alloy during dry machining, and once the deposition occurs, flutes of the cutting edges are instantly filled up with the cut material. When still the machining is forcibly continued, there are cases where the machined face will be extremely deteriorated and, at the worst, the tool will be broken and become incapable of cutting. Meanwhile, in the cemented carbide end mill of a square type, as disclosed in JP-A-2001-293611, the dry machining of an aluminum alloy is realized by applying the coating film having a small coefficient of dynamic friction and improving the deposition resistance.